Specular reflection reduction using polarized light sources

ABSTRACT

A method for generating a composite image includes receiving a first image that includes an eyeglass lens illuminated by a first illumination source radiating electromagnetic radiation in a first polarization state, and receiving a second image that includes the eyeglass lens illuminated by a second illumination source radiating electromagnetic radiation in a second polarization state. The second polarization state is different from the first polarization state, and the second illumination source is spatially separated from the first illumination source. The method also includes identifying, in the first image, a first portion that represents a reflection of the first illumination source on the eyeglass lens, and generating the composite image in which the first portion is replaced by a corresponding second portion from the second image. The first portion and the second portion represent substantially a same portion of the eyeglass lens.

TECHNICAL FIELD

This disclosure relates to image capture devices.

BACKGROUND

Systems incorporating a biometric identification technology such as facerecognition or iris recognition often include a camera that captures animage of a user. The captured image is then processed to authenticatethe user using the biometric identification technology.

SUMMARY

In one aspect, this document describes a method for generating acomposite image from multiple images. The method includes receiving, atone or more processing devices, a first image that includes an eyeglasslens. The eyeglass lens is illuminated by a first illumination sourceradiating electromagnetic radiation in a first polarization state. Themethod also includes receiving, at the one or more processing devices, asecond image that includes the eyeglass lens, wherein the eyeglass lensis illuminated by a second illumination source radiating electromagneticradiation in a second polarization state. The second polarization stateis different from the first polarization state, and the secondillumination source is spatially separated from the first illuminationsource. The method also includes identifying, in the first image, afirst portion that represents a reflection of the first illuminationsource on the eyeglass lens, and generating the composite image in whichthe first portion is replaced by a corresponding second portion from thesecond image. The first portion and the second portion representsubstantially a same portion of the eyeglass lens.

In another aspect, this document describes an imaging system thatincludes a first illumination source controllable to radiateelectromagnetic radiation of multiple polarization states, and a secondillumination source disposed spatially separated from the firstillumination source, the second illumination source controllable toradiate electromagnetic radiation of multiple polarization states. Thesystem also includes one or more processing devices that receive a firstimage captured under illumination by the first illumination sourceradiating electromagnetic radiation in a first polarization state, andreceive a second image under illumination by a second illuminationsource radiating electromagnetic radiation in a second polarizationstate different from the first polarization state. The one or moreprocessing devices also identify, in the first image, a first portionthat represents a reflection of the first illumination source, andgenerate a composite image in which the first portion is replaced by acorresponding second portion from the second image. The first portionand the second portion represent substantially a same portion of asubject captured in the first and second images.

In another aspect, this document describes one or more machine-readablestorage devices having encoded thereon computer readable instructionsfor causing one or more processing devices to perform operations. Theoperations include receiving a first image that includes an eyeglasslens. The eyeglass lens is illuminated by a first illumination sourceradiating electromagnetic radiation in a first polarization state. Theoperations also include receiving a second image that includes theeyeglass lens, wherein the eyeglass lens is illuminated by a secondillumination source radiating electromagnetic radiation in a secondpolarization state. The second polarization state is different from thefirst polarization state, and the second illumination source isspatially separated from the first illumination source. The operationsfurther include identifying, in the first image, a first portion thatrepresents a reflection of the first illumination source on the eyeglasslens, and generating the composite image in which the first portion isreplaced by a corresponding second portion from the second image. Thefirst portion and the second portion represent substantially a sameportion of the eyeglass lens.

Implementations of any of the above aspects can include one or more ofthe following features.

The first illumination source can radiate the electromagnetic radiationin the first polarization state during a first time period, and thesecond illumination source can radiate the electromagnetic radiation inthe second polarization state during a second time period that is atleast partially non-overlapping with the first time period. The firstpolarization state can be substantially orthogonal to the secondpolarization state. A biometric authentication can be performed based onthe composite image. In some implementations, a third portion thatrepresents a reflection of the second illumination source on theeyeglass lens can be identified in a second image, and a secondcomposite image can be generated. In the second composite image, thethird portion can be replaced by a corresponding fourth portion from thefirst image, the third portion and the fourth portion representingsubstantially a same portion of the eyeglass lens. At least one of: (i)a first polarizer disposed at the first illumination source and (ii) asecond polarizer disposed at the second illumination source can becontrolled such that the reflection of the first illumination source onthe eyeglass lens and a reflection of the second illumination source onthe eyeglass lens are at different locations. At least one of (i) thefirst polarization state and (ii) the second polarization state can beadjusted based on an estimate of a strength of reflection associatedwith the reflection of the first illumination source on the eyeglasslens.

At least one camera can be used in capturing the first and secondimages. An authentication engine can process the composite image toperform a biometric authentication process to regulate access to asecure system. A first polarizer can be disposed at the firstillumination source and/or a second polarizer disposed at the secondillumination source. At least one motor can control one or more of thefirst and second polarizers such that the reflection of the firstillumination source on the subject and a reflection of the secondillumination source on the subject are at different locations. At leastone of (i) the first illumination source and (ii) the secondillumination source can be a multispectral source controllable toradiate illumination at multiple different wavelengths. A wavelengthassociated with at least one of (i) the first illumination source and(ii) the second illumination source can be adjusted based on an estimateof a strength of reflection associated with the reflection of the firstillumination source.

Various implementations described herein may provide one or more of thefollowing advantages. By using at least two spatially separatedillumination sources that generate illumination in differentpolarization states, camera sensors can be used to obtain at least twoseparate images where the differently polarized illumination sources arereflected differently. This in turn may be used to generate a compositeimage by replacing a portion of a first image affected by specularreflection from a first illumination source by a corresponding portionfrom a second image which is not affected similarly by the firstillumination source. This in turn can potentially improve the underlyingbiometric authentication systems and/or the usability of such systems invarious applications particularly in processing images of users wearingeyeglasses. For example, the technologies described herein may improvethe performance of a biometricauthentication/identification/verification system by making availableimportant eye or facial features that may otherwise not be discerniblein an image due to reflections of a light source on an eyeglass lens orglare on the eyeball due to ambient lighting conditions.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a kiosk machine as an example environment in which thetechnology described herein may be used.

FIG. 2 is an example illustrating the removal of specular reflectionfrom images of eyeglasses using the technology described herein.

FIG. 3 shows an example scheme of illumination that may be generatedusing two spatially separated illumination sources

FIG. 4 shows an example of a system that can be used to implement thetechnology described herein.

FIG. 5 is a flowchart of an example process for generating a compositeimage in accordance with technology described herein.

FIG. 6 is a block diagram representing examples of computing devices.

Repeat use of reference characters in the present specification anddrawings is intended to represent same or analogous features orelements.

DETAILED DESCRIPTION

This document describes technology that allows for removing reflections(e.g., specular reflections) from images captured in the presence of oneor more artificial illumination sources such as light emitting diode(LED) lights. Various biometric identification/authentication systemsare based on capturing one or more images, which are then compared withor analyzed with reference to template images captured during anenrollment process. For example, a biometric authentication system thatuses face identification may require enrolling users to pose for one ormore images of their face during an enrollment process. The imagescaptured during the enrollment process may be stored on a storage deviceaccessible to the biometric authentication system. During run-time, afacial image of a user can be captured and compared with one or moretemplate images to determine if the user may be identified/verified. Therun-time images may be captured using one or more artificialillumination sources, which in turn may produce specular reflections ofthe illumination sources on the subject, e.g., on the lenses ofeyeglasses worn by the subject. In some cases, such specular reflectionsmay be detrimental to the underlying biometric authentication process,for example, by occluding eye or facial features that may otherwise beused by the process. In some cases, this may affect the accuracy and/orefficiency of the underlying biometric authentication system, forexample by adversely affecting the false positive and/or the falsenegative rates.

The technology described herein allows for mitigating adverse effects ofspecular reflections on biometric authentication processes via thegeneration of a composite image from multiple images that are capturedunder differently polarized illumination. For example, the polarizationstates of multiple spatially separated illumination sources may bevaried (e.g., by controlling polarization angles of polarizers disposedin front of the individual sources) such that the individual lightsources radiate light that are differently polarized. Because lights ofdifferent polarization states reflect off a surface differently,specular reflections due to two spatially separated light sourcespolarized in different ways are likely to appear in two differentlocations. If multiple images of the subject are captured underillumination of different polarization states, portions of one imagethat is affected by specular reflection due to one source may bereplaced by corresponding portions from another image captured underillumination by another source. It could also be used to mitigate theglare on the surface of the eyeball due to light source or ambientlighting conditions. Other similar conditions include minimizing thespecular reflections on reflective surface of the skin such assweaty/oily forehead and lower periocular region etc.

When used in subsequent biometric processing, such composite images mayimprove the accuracy and/or efficiency of the underlying biometricauthentication technology. Multiple images captured under illuminationby different spatially-separated light sources may be used to generate a3D representation of the target using photometric stereo reconstructiontechniques. Such 3D representations may in turn be used inspoof-detection, for example, by differentiating from 2D images of thesame target.

FIG. 1 shows a kiosk machine 100 as an example environment in which thetechnology described herein may be used. Such kiosk machines may be usedfor various purposes that require identifying/verifying users via one ormore biometric authentication processes. For example, the kiosk 100 caninclude an ATM that allows a user to withdraw money from a bank account.In another example, the kiosk 100 may be deployed at a restaurant or afast-food outlet, and allow a user to order and pay for food. The kiosk100 may also be deployed at an entry point (e.g., at the gate of anarena or stadium) to identify/verify entrants prior to entering thevenue. In general, the kiosk 100 may be deployed at various types oflocations to identify/verify users interactively, or even without anyactive participation of the user.

In some implementations, the kiosk 100 can include one or morecomponents that support a biometric authentication system. For example,the kiosk 100 can include a camera 105 that captures images of usersinteracting with the kiosk 100. The captured images may be processed toidentify/verify valid users, and/or permit or deny access to theservices/products being offered through the kiosk. For example, thekiosk 100 may include a display device 110 (e.g., a capacitive touchscreen) that allows a user to select and order food at a retail outlet.Once the user completes the selection via user-interfaces presented onthe display device 110, the user may be asked to look towards the camera105 for authentication. The images captured using the camera 105 maythen be used to verify/identify a pre-stored profile for the user, andthe payment for the food may then be automatically deducted from anaccount linked to the profile. While FIG. 1 shows a single camera 105,multiple cameras may be used in some implementations. For example, twocameras each having a front end polarizer configured to pass light of aparticular polarization state may be used. In such cases, even when thesubject is simultaneously illuminated with lights of two differentpolarization states, each camera captures an image corresponding toillumination under a particular polarization state. In someimplementations, a single camera 105 can have a controllable polarizerdisposed in front of the camera such that the light entering the cameracan be actively controlled. For example, a motor can be deployed tocontrol the polarization angle of the camera polarizer such that thecamera 105 captures an image of a subject under illumination of a firstpolarization state during a particular time-period, and another image ofthe same subject under illumination of a second polarization stateduring another time-period.

In some implementations, the images captured using the camera 105 can beprocessed using an underlying biometric authentication system toidentify/verify the user. In some implementations, the biometricauthentication system may extract from the images, various features—suchas features derived from the face, iris, vasculature underlying thesclera of the eye, or the periocular region—to identify/verify aparticular user based on matching the extracted features to that of oneor more template images stored for the user during an enrollmentprocess. The biometric authentication system may use a machine-learningprocess (e.g., a deep learning process implemented, for example, using adeep neural network architecture) to match the user to one of the manytemplates stored for various users of the system. In someimplementations, the machine learning process may be implemented, atleast in part, using one or more processing devices deployed on thekiosk 100. In some implementations, the kiosk 100 may communicate withone or more remote processing devices (e.g., one or more remote servers)that implement the machine learning process.

In some implementations, the kiosk 100 can include at least twoillumination sources 115 a and 115 b (115, in general) that arespatially separated from one another by a known distance, and areconfigured to generate electromagnetic radiation. The illuminationsources may be inherently polarized differently from one another, or befitted with a polarizer that impart particular polarization states tothe light being radiated by the corresponding sources 115. In someimplementations, the polarizers disposed in front of the illuminationsources 115 can be active polarizers the polarization angles of whichmay be controllable, for example via a motor. In such cases, thepolarization states associated with the illumination sources 115 may beactively controlled, possibly in conjunction with a polarizer associatedwith the camera 105, such that the two illumination sources emit lightthat are differently polarized.

The illumination sources 115 can each include one or more light emittingdiode (LED) elements 120 that may be controlled to generateelectromagnetic radiation. In some implementations, the LED elements 120can be configured to emit radiation at multiple wavelengths orwavelength ranges. The wavelength ranges can include the visiblespectrum of about 400-700 nm, the NIR spectrum of about 700-1000 nm,SWIR spectrum of about 1000-1600 nm and/or near-UV wavelengths in the320-400 nm range. While the example in FIG. 1 shows only twoillumination sources 115 that are physically separated along ahorizontal direction, various other configurations are also possible.For example, the illumination sources 115 may be separated along avertical direction, and/or more than two illumination sources may beused.

In some implementations, reflections (e.g., specular reflections) of anillumination source from a user's eyeglasses may degrade the quality ofcaptured images, and in turn interfere with biometric authenticationprocesses such as those based on detecting iris patterns or eyevasculature. FIG. 2 is an example illustrating the removal of specularreflection from images of eyeglasses using the technology describedherein. In this example, the upper image 200 represents an imagecaptured under illumination of a particular polarization state (referredto herein as P1). The lower image 250 represents an image captured underillumination of another polarization state (referred to herein as P2).Because the polarization states P1 and P2 correspond to two differentsources that are spatially separated, the specular reflectionscorresponding to the two sources appear in different portions of thecorresponding images. For example, the specular reflection 205 of onesource in image 200 and the specular reflection 255 of the other sourcein image 250 are located in different portions of the correspondingimages. Therefore, if the images 200 and 250 are captured sufficientlyclose in time (e.g., within a time period in which the user is unlikelyto change positions significantly), the specular reflection in one imagecan be removed, for example, by replacing the corresponding pixel valuesin the image with analogous pixel values from the other image. Forexample, the pixel values corresponding to the reflection 205 in theimage 200 can be replaced by pixel values from an analogous region orportion 260 from the image 250. Similarly, the pixel valuescorresponding to the reflection 255 in the image 250 can be replaced bypixel values from an analogous region 210 from the image 200. Thisallows for generation of one or more composite images from the multipleoriginal images. This can be done via replacing, in one image, pixelvalues due to specular reflection (which carries little or no meaningfulinformation about the target) with meaningful pixel values fromcorresponding portions of another image. In some cases, this may improvethe underlying biometric authentication process, and/or improve theappearance of the resulting image.

The multiple images corresponding to different polarization states canbe captured in multiple ways. In some implementations, the illuminationsource 115 a radiates illumination of a particular polarization state(e.g., P1) during a time period that is at least partiallynon-overlapping with the time period during which the illuminationsource 115 b radiates illumination at another polarization states P2.FIG. 3 shows an example set of two illumination sequences that may begenerated using the two spatially separated illumination sources.Specifically, the illumination source 115 a radiates illumination withpolarization state P1 during the time period t1 and the illuminationsource 115 b radiates illumination with polarization state P2 during thetime period t2. This can then be repeated as shown in FIG. 3. While theexamples in FIG. 3 represents the time periods t1 and t2 to besubstantially equal to each other, the bit durations may also bedifferent from one another. The duration of the time periods t1, t2 canbe selected based on particular applications and/or the hardwarecapabilities. In some implementations, two cameras with correspondingfront end polarizers can be deployed to capture images during the timeperiod t1 and t2, respectively. In some implementations, an activepolarizer disposed in front of a single camera may be adjusted such thatthe camera captures an image under P1 polarization state during t1, andanother image under P2 polarization state during t2.

In some implementations, the illumination sources 115 a and 115 b mayradiate illumination of different polarization states substantiallyconcurrently. In such cases, the multiple images corresponding todifferent polarization states can be captured either using multiplecameras, or by adjusting an active polarizer associated with a singlecamera. For example, if the two illuminations sources 115 a and 115 bare configured to radiate illumination of mutually orthogonalpolarization states concurrently, an active polarizer of a camera can beadjusted such that illumination of polarization state P1 reaches thecamera sensors during t1 (while polarization state P2 is blocked out),and illumination of polarization state P2 reaches the camera sensorsduring t2 (while polarization state P1 is blocked out). While theconcepts are illustrated using only two polarization states, highernumber of polarization states (and correspondingly captured images) canbe used without deviating from the scope of this disclosure. Forexample, each of multiple illumination sources and the camera(s) caninclude corresponding active polarizers that are controllable, forexample, using a motor. The active polarizers can be controlled inconjunction with one another such that the spatially separated lightsources radiate light of different polarization states (eitherconcurrently or sequentially), and correspondingly the camera(s) capturethe multiple images that correspond to illumination od individualpolarization states. Either linear or circular polarizers can be usedfor implementing the technology described herein.

In some implementations, the illumination sources 115 a and 115 b mayradiate illumination of different wavelengths. In some implementations,the illumination sources 115 can be multispectral sources (e.g.,multispectral LEDs) that can be controlled to radiate lights ofdifferent wavelengths. In some implementations, the wavelengths of theillumination sources 115 can be controlled in conjunction with thecorresponding polarization states to generate the composite images inaccordance with technology described herein. In some implementations, atleast one of the illumination sources 115 can be adjusted based on anestimate of a strength of reflection associated with the reflection ofthe corresponding source on the subject. The strength of reflection canbe estimated, for example, based on pixel values in the correspondingportions of the image. For example, a high average pixel value over theportions representing a reflection can indicate a strong reflection andvice versa. In some implementations, the wavelength associated with asource can be varied such that that the strength of reflection isreduced. In some implementations, the polarization state (e.g., angle ofpolarization) of a polarizer 420 may be varied based on an estimatedstrength of a corresponding reflection.

FIG. 4 shows an example of a system 400 that can be used to implementthe technology described herein. At least a portion of the system 400can be implemented as a portion of a kiosk 100, as described above withreference to FIG. 1. For example, the system 400 can include one or moreillumination sources 115 a, 115 b etc. (115, in general), and one ormore cameras 105, substantially similar to those described above. Insome implementations, the system 400 includes an image capture engine405 that controls and coordinates the operations of the one moreillumination sources 115 and the cameras 105 in accordance withtechnology described herein. The image capture engine 405 can includeone or more processing devices 415 that control one or more componentsof the system 400. For example, the one or more processing devices 415of the image capture engine 405 can be used to control the camera 105,as well as one or more motors 410 that adjusts one or more polarizers420 a, 420 b, 420 c, etc. (420 in general). In some implementations, themotors 410 are in communication with polarizers 420 a and 420 bassociated with the illumination sources 115 a and 115 b, respectively.

The one or more processing devices 415 of the image capture engine 405can be configured to control the motors to adjust the polarizers 420 aand 420 b such that the corresponding illuminations sources 115 radiatelight with different polarizations. The motors 410 can also beconfigured to control a polarizer 420 c associated with the camera 105such that the camera 105 can be selectively used to capture images underillumination of a particular polarization state. For example, if theillumination sources 115 a and 115 b are configured to radiate lightwith illumination states P1 and P2, respectively, the polarizer 420 cmay be controlled by the motors 410 such that the camera sequentiallycaptures (i) a first image substantially under illumination of P1polarization state (while blocking illumination of the P2 polarizationstate), and (ii) a second image substantially under illumination of P2polarization state (while blocking illumination of the P2 polarizationstate). In some implementations, the polarization states of thepolarizers 420 a and 420 b can be varied (while keeping them differentwith respect to one another), and the polarizer 420 c can be adjustedaccordingly to facilitate capturing corresponding images. In someimplementations, the angle of polarization state in the polarizer 420 cmay be varied, for example, based on an estimated strength of reflectionin the captured video feed from the camera in 105. The strength ofreflection can be estimated, for example, based on pixel values in thecorresponding portions of the image. For example, a high average pixelvalue over the portions representing a reflection can indicate a strongreflection and vice versa. In some implementations, the polarizationstate (e.g., an angle of polarization) can be varied such that that thestrength of reflection is reduced.

FIG. 5 is a flowchart of an example process 500 for generating acomposite image in accordance with technology described herein. In someimplementations, at least a portion of the process 500 may be executedby one or more processing devices disposed within a kiosk such as thekiosk 100 described with reference to FIG. 1. In some implementations,at least a portion of the process 500 may be executed at one or moreservers (such as servers or computing devices in a distributed computingsystem) in communication with remote components such as one or moreprocessing devices disposed within a kiosk. In some implementations, atleast a portion of the process 500 can be executed by the one or moreprocessing devices 415 of the image capture engine 405.

Operations of the process 500 includes receiving a first image thatincludes an eyeglass lens, wherein the eyeglass lens is illuminated by afirst illumination source radiating electromagnetic radiation in a firstpolarization state (510). Operations of the process 500 also includesreceiving a second image that includes the eyeglass lens, wherein theeyeglass lens is illuminated by a second illumination source radiatingelectromagnetic radiation in a second polarization state (520). Thesecond polarization state is different from the first polarizationstate. For example, the first and second polarization states can besubstantially orthogonal to one another. The second illumination sourceis spatially separated from the first illumination source.

In some implementations, the first and second images are captured usinga single camera during two time periods that are at least partiallynon-overlapping. In some implementations, the first and second imagesare captured substantially concurrently with at least two cameras eachof which allows the reflected light corresponding to one polarization topass while substantially blocking the reflected light corresponding tothe other polarization state. In some implementations, the firstillumination source radiates the electromagnetic radiation in the firstpolarization state during a first time period, and the secondillumination source radiates the electromagnetic radiation in the secondpolarization state during a second time period that is at leastpartially non-overlapping with the first time period.

Operations of the process 500 also includes identifying, in the firstimage, a first portion that represents a reflection of the firstillumination source on the eyeglass lens (530) and generating acomposite image in which the first portion is replaced by acorresponding second portion from the second image (540). The firstportion and the second portion represent substantially a same portion ofthe eyeglass lens. For example, the polarization states of the firstillumination source and the second illumination source may be controlledsuch that specular reflections of the sources on the lenses are atdifferent locations. This can include, for example, controlling at leastone of (i) a first polarizer disposed at the first illumination sourceand (ii) a second polarizer disposed at the second illumination sourcesuch that the reflection of the first illumination source on theeyeglass lens and a reflection of the second illumination source on theeyeglass lens are at different locations. In some implementations,generating the composite image can include identifying, in the secondimage, a particular portion that represents a reflection of the secondillumination source on the eyeglass lens, and generating the compositeimage by replacing pixel values corresponding to the particular portionof the second image by pixel values in a corresponding portion from thefirst image. The portions replaced by one another representsubstantially a same portion of the imaged subject (e.g., same portionsof the eyeglass lens on which the specular reflections are visible). Thecomposite images can then be used in a biometric authentication processsuch as ones based on analyzing irises, eyeprints, or other facialfeatures.

FIG. 6 shows an example of a computing device 600 and a mobile device650, which may be used with the techniques described here. For example,referring to FIG. 1, the kiosk device 100 can include one or more of thecomputing device 600 or the mobile device 650, either in part or in itsentirety. Computing device 600 is intended to represent various forms ofdigital computers, such as laptops, desktops, workstations, personaldigital assistants, servers, blade servers, mainframes, and otherappropriate computers. Computing device 650 is intended to representvarious forms of mobile devices, such as personal digital assistants,cellular telephones, smartphones, and other similar computing devices.The components shown here, their connections and relationships, andtheir functions, are meant to be examples only, and are not meant tolimit implementations of the techniques described and/or claimed in thisdocument.

Computing device 600 includes a processor 602, memory 604, a storagedevice 606, a high-speed interface 608 connecting to memory 604 andhigh-speed expansion ports 610, and a low speed interface 612 connectingto low speed bus 614 and storage device 606. Each of the components 602,604, 606, 608, 610, and 612, are interconnected using various busses,and may be mounted on a common motherboard or in other manners asappropriate. The processor 602 can process instructions for executionwithin the computing device 600, including instructions stored in thememory 604 or on the storage device 606 to display graphical informationfor a GUI on an external input/output device, such as display 616coupled to high speed interface 608. In other implementations, multipleprocessors and/or multiple buses may be used, as appropriate, along withmultiple memories and types of memory. Also, multiple computing devices600 may be connected, with each device providing portions of thenecessary operations (e.g., as a server bank, a group of blade servers,or a multi-processor system).

The memory 604 stores information within the computing device 600. Inone implementation, the memory 604 is a volatile memory unit or units.In another implementation, the memory 604 is a non-volatile memory unitor units. The memory 604 may also be another form of computer-readablemedium, such as a magnetic or optical disk.

The storage device 606 is capable of providing mass storage for thecomputing device 600. In one implementation, the storage device 606 maybe or contain a computer-readable medium, such as a floppy disk device,a hard disk device, an optical disk device, or a tape device, a flashmemory or other similar solid state memory device, or an array ofdevices, including devices in a storage area network or otherconfigurations. A computer program product can be tangibly embodied inan information carrier. The computer program product may also containinstructions that, when executed, perform one or more methods, such asthose described above. The information carrier is a computer- ormachine-readable medium, such as the memory 604, the storage device 606,memory on processor 602, or a propagated signal.

The high speed controller 608 manages bandwidth-intensive operations forthe computing device 600, while the low speed controller 612 manageslower bandwidth-intensive operations. Such allocation of functions is anexample only. In one implementation, the high-speed controller 608 iscoupled to memory 604, display 616 (e.g., through a graphics processoror accelerator), and to high-speed expansion ports 610, which may acceptvarious expansion cards (not shown). In the implementation, low-speedcontroller 612 is coupled to storage device 606 and low-speed expansionport 614. The low-speed expansion port, which may include variouscommunication ports (e.g., USB, Bluetooth, Ethernet, wireless Ethernet)may be coupled to one or more input/output devices, such as a keyboard,a pointing device, a scanner, or a networking device such as a switch orrouter, e.g., through a network adapter.

The computing device 600 may be implemented in a number of differentforms, as shown in the figure. For example, it may be implemented as astandard server 620, or multiple times in a group of such servers. Itmay also be implemented as part of a rack server system 624. Inaddition, it may be implemented in a personal computer such as a laptopcomputer 622. Alternatively, components from computing device 600 may becombined with other components in a mobile device (not shown), such asdevice 650. Each of such devices may contain one or more of computingdevice 600, 650, and an entire system may be made up of multiplecomputing devices 600, 650 communicating with each other.

Computing device 650 includes a processor 652, memory 664, aninput/output device such as a display 654, a communication interface666, and a transceiver 668, among other components. The device 650 mayalso be provided with a storage device, such as a microdrive or otherdevice, to provide additional storage. Each of the components 650, 652,664, 654, 666, and 668, are interconnected using various buses, andseveral of the components may be mounted on a common motherboard or inother manners as appropriate.

The processor 652 can execute instructions within the computing device650, including instructions stored in the memory 664. The processor maybe implemented as a chipset of chips that include separate and multipleanalog and digital processors. The processor may provide, for example,for coordination of the other components of the device 650, such ascontrol of user interfaces, applications run by device 650, and wirelesscommunication by device 650.

Processor 652 may communicate with a user through control interface 658and display interface 656 coupled to a display 654. The display 654 maybe, for example, a TFT LCD (Thin-Film-Transistor Liquid Crystal Display)or an OLED (Organic Light Emitting Diode) display, or other appropriatedisplay technology. The display interface 656 may comprise appropriatecircuitry for driving the display 654 to present graphical and otherinformation to a user. The control interface 658 may receive commandsfrom a user and convert them for submission to the processor 652. Inaddition, an external interface 662 may be provide in communication withprocessor 652, so as to enable near area communication of device 650with other devices. External interface 662 may provide, for example, forwired communication in some implementations, or for wirelesscommunication in other implementations, and multiple interfaces may alsobe used.

The memory 664 stores information within the computing device 650. Thememory 664 can be implemented as one or more of a computer-readablemedium or media, a volatile memory unit or units, or a non-volatilememory unit or units. Expansion memory 674 may also be provided andconnected to device 650 through expansion interface 672, which mayinclude, for example, a SIMM (Single In Line Memory Module) cardinterface. Such expansion memory 674 may provide extra storage space fordevice 650, or may also store applications or other information fordevice 650. Specifically, expansion memory 674 may include instructionsto carry out or supplement the processes described above, and mayinclude secure information also. Thus, for example, expansion memory 674may be provide as a security module for device 650, and may beprogrammed with instructions that permit secure use of device 650. Inaddition, secure applications may be provided via the SIMM cards, alongwith additional information, such as placing identifying information onthe SIMM card in a non-hackable manner.

The memory may include, for example, flash memory and/or NVRAM memory,as discussed below. In one implementation, a computer program product istangibly embodied in an information carrier. The computer programproduct contains instructions that, when executed, perform one or moremethods, such as those described above. The information carrier is acomputer- or machine-readable medium, such as the memory 664, expansionmemory 674, memory on processor 652, or a propagated signal that may bereceived, for example, over transceiver 668 or external interface 662.

Device 650 may communicate wirelessly through communication interface666, which may include digital signal processing circuitry wherenecessary. Communication interface 666 may provide for communicationsunder various modes or protocols, such as GSM voice calls, SMS, EMS, orMMS messaging, CDMA, TDMA, PDC, WCDMA, CDMA2000, or GPRS, among others.Such communication may occur, for example, through radio-frequencytransceiver 668. In addition, short-range communication may occur, suchas using a Bluetooth, WiFi, or other such transceiver (not shown). Inaddition, GPS (Global Positioning System) receiver module 670 mayprovide additional navigation- and location-related wireless data todevice 650, which may be used as appropriate by applications running ondevice 650.

Device 650 may also communicate audibly using audio codec 660, which mayreceive spoken information from a user and convert it to usable digitalinformation. Audio codec 660 may likewise generate audible sound for auser, such as through a speaker, e.g., in a handset of device 650. Suchsound may include sound from voice telephone calls, may include recordedsound (e.g., voice messages, music files, and so forth) and may alsoinclude sound generated by applications operating on device 650.

The computing device 650 may be implemented in a number of differentforms, as shown in the figure. For example, it may be implemented as acellular telephone 680. It may also be implemented as part of asmartphone 682, personal digital assistant, tablet computer, or othersimilar mobile device.

Various implementations of the systems and techniques described here canbe realized in digital electronic circuitry, integrated circuitry,specially designed ASICs (application specific integrated circuits),computer hardware, firmware, software, and/or combinations thereof.These various implementations can include implementation in one or morecomputer programs that are executable and/or interpretable on aprogrammable system including at least one programmable processor, whichmay be special or general purpose, coupled to receive data andinstructions from, and to transmit data and instructions to, a storagesystem, at least one input device, and at least one output device.

These computer programs (also known as programs, software, softwareapplications or code) include machine instructions for a programmableprocessor, and can be implemented in a high-level procedural and/orobject-oriented programming language, and/or in assembly/machinelanguage. As used herein, the terms “machine-readable medium”“computer-readable medium” refers to any computer program product,apparatus and/or device (e.g., magnetic discs, optical disks, memory,Programmable Logic Devices (PLDs)) used to provide machine instructionsand/or data to a programmable processor, including a machine-readablemedium that receives machine instructions.

To provide for interaction with a user, the systems and techniquesdescribed here can be implemented on a computer having a display device(e.g., a CRT (cathode ray tube) or LCD (liquid crystal display) monitor)for displaying information to the user and a keyboard and a pointingdevice (e.g., a mouse or a trackball) by which the user can provideinput to the computer. Other kinds of devices can be used to provide forinteraction with a user as well. For example, feedback provided to theuser can be any form of sensory feedback (e.g., visual feedback,auditory feedback, or tactile feedback). Input from the user can bereceived in any form, including acoustic, speech, or tactile input.

The systems and techniques described here can be implemented in acomputing system that includes a back end component (e.g., as a dataserver), or that includes a middleware component (e.g., an applicationserver), or that includes a front end component (e.g., a client computerhaving a graphical user interface or a Web browser through which a usercan interact with an implementation of the systems and techniquesdescribed here), or any combination of such back end, middleware, orfront end components. The components of the system can be interconnectedby any form or medium of digital data communication (e.g., acommunication network). Examples of communication networks include alocal area network (“LAN”), a wide area network (“WAN”), and theInternet.

The computing system can include clients and servers. A client andserver are generally remote from each other and typically interactthrough a communication network. The relationship of client and serverarises by virtue of computer programs running on the respectivecomputers and having a client-server relationship to each other.

This specification uses the term “configured” in connection with systemsand computer program components. For a system of one or more computersto be configured to perform particular operations or actions means thatthe system has installed on it software, firmware, hardware, or acombination of them that in operation cause the system to perform theoperations or actions. For one or more computer programs to beconfigured to perform particular operations or actions means that theone or more programs include instructions that, when executed by dataprocessing apparatus, cause the apparatus to perform the operations oractions.

In this specification the term “engine” is used broadly to refer to asoftware-based system, subsystem, or process that is programmed toperform one or more specific functions. Generally, an engine will beimplemented as one or more software modules or components, installed onone or more computers in one or more locations. In some cases, one ormore computers will be dedicated to a particular engine, in other cases,multiple engines can be installed and running on the same computer orcomputers.

Although a few implementations have been described in detail above,other modifications may be made without departing from the scope of theinventive concepts described herein, and, accordingly, otherimplementations are within the scope of the following claims.

1. A method for generating a composite image from multiple images, themethod comprising: receiving, by one or more processing devices, a firstimage that includes an eyeglass lens, wherein the eyeglass lens isilluminated by a first illumination source radiating electromagneticradiation in a first polarization state; receiving, by the one or moreprocessing devices, a second image that includes the eyeglass lens,wherein the eyeglass lens is illuminated by a second illumination sourceradiating electromagnetic radiation in a second polarization state,wherein: a reflection of the second illumination source on the eyeglasslens and a reflection of the first illumination source on the eyeglasslens are at different locations, the second polarization state isdifferent from the first polarization state and the second illuminationsource is spatially separated from the first illumination source;identifying, by the one or more processing devices in the first image, afirst portion that represents the reflection of the first illuminationsource on the eyeglass lens; identifying, by the one or more processingdevice in the second image, a second portion corresponding to the firstportion of the first image, wherein: the second portion does notrepresent the reflection of the second illumination source on theeyeglass lens, and the first portion and the second portion represent asame portion of the eyeglass lens; and generating, by the one or moreprocessing devices, the composite image in which the first portion isreplaced by the corresponding second portion from the second image. 2.The method of claim 1, wherein the first illumination source radiatesthe electromagnetic radiation in the first polarization state during afirst time period, and the second illumination source radiates theelectromagnetic radiation in the second polarization state during asecond time period that is at least partially non-overlapping with thefirst time period.
 3. The method of claim 1, wherein the firstpolarization state is substantially orthogonal to the secondpolarization state.
 4. The method of claim 1, further comprisingperforming a biometric authentication based on the composite image. 5.The method of claim 1, further comprising: identifying, in a secondimage, a third portion that represents the reflection of the secondillumination source on the eyeglass lens; and generating, by the one ormore processing devices, a second composite image in which the thirdportion is replaced by a corresponding fourth portion from the firstimage, wherein the third portion and the fourth portion represent a sameportion of the eyeglass lens.
 6. The method of claim 1, furthercomprising controlling at least one of: (i) a first polarizer disposedat the first illumination source and (ii) a second polarizer disposed atthe second illumination source such that the reflection of the firstillumination source on the eyeglass lens and the reflection of thesecond illumination source on the eyeglass lens are at differentlocations.
 7. The method of claim 1, wherein at least one of (i) thefirst polarization state and (ii) the second polarization state isadjusted based on an estimate of a strength of reflection associatedwith the reflection of the first illumination source on the eyeglasslens.
 8. The method of claim 1, wherein a wavelength associated with atleast one of (i) the first illumination source and (ii) the secondillumination source is adjusted based on an estimate of a strength ofreflection associated with the reflection of the first illuminationsource on the eyeglass lens.
 9. An imaging system comprising: a firstillumination source controllable to radiate electromagnetic radiation ofmultiple polarization states; a second illumination source disposedspatially separated from the first illumination source, the secondillumination source controllable to radiate electromagnetic radiation ofmultiple polarization states; and one or more processing devices that:receive a first image including a subject captured under illumination bythe first illumination source radiating electromagnetic radiation in afirst polarization state, receive a second image including the subjectunder illumination by the second illumination source radiatingelectromagnetic radiation in a second polarization state different fromthe first polarization state, wherein a reflection of the secondillumination source on the subject and a reflection of the firstillumination source on the subject are at different locations, identify,in the first image, a first portion that represents the reflection ofthe first illumination source, identifying, in the second image, asecond portion corresponding to the first portion of the first image,wherein: the second portion does not represent the reflection of thesecond illumination source on the subject, and the first portion and thesecond portion represent a same portion of the subject; and generate acomposite image in which the first portion is replaced by thecorresponding second portion from the second image.
 10. The system ofclaim 9, wherein the first illumination source radiates theelectromagnetic radiation in the first polarization state during a firsttime period, and the second illumination source radiates theelectromagnetic radiation in the second polarization state during asecond time period that is at least partially non-overlapping with thefirst time period.
 11. The system of claim 9, wherein the firstpolarization state is substantially orthogonal to the secondpolarization state.
 12. The system of claim 9, further comprising atleast one camera that captures the first and second images.
 13. Thesystem of claim 9, further comprising an authentication engine thatprocesses the composite image to perform a biometric authenticationprocess to regulate access to a secure system.
 14. The system of claim9, wherein the one or more processing devices are configured to:identify, in the second image, a third portion that represents thereflection of the second illumination source; and generate a secondcomposite image in which the third portion is replaced by acorresponding fourth portion from the first image, wherein the thirdportion and the fourth portion represent a same portion of the subject.15. The system of claim 9, further comprising: at least one of: (i) afirst polarizer disposed at the first illumination source and (ii) asecond polarizer disposed at the second illumination source.
 16. Thesystem of claim 15, further comprising at least one motor that controlsone or more of the first and second polarizers such that the reflectionof the first illumination source on the subject and the reflection ofthe second illumination source on the subject are at differentlocations.
 17. The system of claim 9, wherein at least one of (i) thefirst polarization state and (ii) the second polarization state isadjusted based on an estimate of a strength of reflection associatedwith the reflection of the first illumination source.
 18. The system ofclaim 9, wherein at least one of (i) the first illumination source and(ii) the second illumination source is a multispectral sourcecontrollable to radiate illumination at multiple different wavelengths.19. The system of claim 18, wherein a wavelength associated with atleast one of (i) the first illumination source and (ii) the secondillumination source is adjusted based on an estimate of a strength ofreflection associated with the reflection of the first illuminationsource.
 20. One or more non-transitory machine-readable storage deviceshaving encoded thereon computer readable instructions for causing one ormore processing devices to perform operations comprising: receiving afirst image that includes an eyeglass lens, wherein the eyeglass lens isilluminated by a first illumination source radiating electromagneticradiation in a first polarization state; receiving a second image thatincludes the eyeglass lens, wherein the eyeglass lens is illuminated bya second illumination source radiating electromagnetic radiation in asecond polarization state, wherein: a reflection of the secondillumination source on the eyeglass lens and a reflection of the firstillumination source on the eyeglass lens are at different locations, thesecond polarization state is different from the first polarizationstate, and the second illumination source is spatially separated fromthe first illumination source; identifying, in the first image, a firstportion that represents the reflection of the first illumination sourceon the eyeglass lens; identifying, in the second image, a second portioncorresponding to the first portion of the first image, wherein: thesecond portion does not represent the reflection of the secondillumination source on the eyeglass lens, and the first portion and thesecond portion represent a same portion of the eyeglass lens; andgenerating a composite image in which the first portion is replaced bythe corresponding second portion from the second image.